Front-end construction for rock drills



Aug. 25, 1936. J. c. CURTIS I FRONT END CONSTRUCTION FOR ROCK DRILLS Filed Aug. 12, 1935 INVENTOR ATTORNEY Patented Aug. 25, 1936 UNITED STATE OFFlGE-Z Application August 12, 1935, Serial No. 35,716,

V 5 Claims. This invention relates broadly to rock drills of the fluid actuated percussive type, but more par ticularly to the front end construction of such. rock drills having an anvil block for transmitting the blows of the hammer piston to the tool ele-.

ment.

In drilling holes, especially overhead holes, with a rock drill equipped with a flashing system for removing the chips from the drilled hole, the Water will run down the drill steel and enter the rock drill between the drill steel and the front housing, from where it is liable to carry dust and other extraneous matter into the operative parts of the drill. The. anvil block being immediately below the drill steel, the water will flow between the anvil block and its housing, thus causing premature wear of the anvil block, as well as permitting further penetration of extraneous matter into other operative parts of the rock drill.

One object of this invention is to produce a front end construction for rock drill with means preventing the admission of extraneous matter from the front end of the drill into the operative parts thereof.

Other objects and advantages more or less ancillary to the foregoing reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination of this specification.

The accompanying drawing represents a sectional elevational view of the front end of a rock drill constructed in accordance with the practice of the invention.

Referring more particularly to the drawing, Ill designates the front portion of the rock drill cylinder having a hammer I I reciprocable therein. The movement of the hammer away from the front end of the cylinder is effected by motive fluid admitted therein through a passage I2. Mounted in the extreme front end of the cylinder I0, there is a front cylinder washer I3 having a flange I4 in abutment with the front end face of the cylinder. This front cylinder washer serves as a guide for an anvil block I5 having an enlarged portion or head I6 protruding from the front end of the washer, and a restricted portion or shank I'I extending into the cylinder for receiving the blows of the hammer I I. Intermediate its ends, the anvil block I5 is provided with a tapered shoulder I8 engageable with a corresponding seat l9, formed in the cylinder washer I3, for limiting the movement of the anvil block toward the cylinder I0. Mounted on the front portion of the cylinder washer I3, and extending forwardly therefrom, there is. a front housing 29. provided.- with a longitudinally disposed. bore 2I adapted to slidably receive. a. tool implement or drill steel 22, which rests on the front face of. the anvil-blockhead I 6. Toward; the anvil block I5, 5 the bore 2 Ifis enlarged. to form a chamber 23. within which the head: I6. of the. anvil block is free to slide for. distributing blows to the drill. steel 22..

Referring more particularly to the present in- 10 vention, 24 designates an annular internal groove formed. in the forwardend of the cylinder'washer I3 around. the anvil block head. Iii- This. groove is. in. constant communication with the chamber 23 through an annular clearance 25, provided be- 15 tween the anvil block head I6 and the cylinder washer I3. Opening into the groove 24, there is a port 26 in communication with a port 21 formed in the wall of the cylinder I0.

The housing 20 is also provided with an internal 20 annular groove 28, which is formed in the forward end portion thereof around the drill steel 22. i his last groove is in constant communication with the chamber 23 through a port 29.

During the operation of the device, pressure 25 fluid, from any suitable source is constantly admitted into the groove 24 through the ports 26 and 21. From the groove 24, the pressure fluid is free to escape around the anvil block head It into the chamber 23 through the annular clear- 30 ance 25. From the chamber 23, the fluid will flow through the port 29 into the annular groove 28, from where it will be free to escape to the exterior of the housing around the drill steel 22. The water running down the drill steel, or any 35 foreign matter falling from the drilled hole, will be prevented to enter the rock drill between the drill steel and housing 20, due to the constant jet of pressure fluid escaping from the front end of the bore 2| around the drill steel 22. However, should any foreign matter find its way into the chamber 23, it will be prevented to pass between the anvil block I6 and cylinder washer I3, due to the constant flow of the pressure fluid escaping 45 from the groove 24 around the anvil block head It via the annular clearance 25.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be under- 50 stood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from the 55 scope or spirit of the invention as herein claimed.

I claim:

1. In a front end construction for rock drills, the combination of a casing having a drill steel slidable therein, an anvil block in abutting engagement with said drill steel, an element within which said anvil block is slidably guided, and means including an annular clearance between the engageable wall of said anvil block with said element for circumferentially supplying pressure fluid to the forward extremity of the bearing between said anvil block and element to keep said bearing free from dirt and other extraneous matter.

2. In a front end construction for rock drills,

the combination of a casing having a drill steel slidable therein, an anvil block in abutment with said drill steel, an element within which said anvil block is slidably guided, and means for supplying pressure fiuid circumferentially through the forward extremity of said element around said anvil block'to keep the bearing between the latter and saidelement free from dirt and other extraneous matter.

' 3. In a front end construction for rock drills, the combination of a casing having a drill steel slidable therein, an anvil block in abutment with said drill steel, an element within which said anvil block is slidably guided, a groove within said element having pressure fluid supplied thereto, and means affording the pressure fluid to flow from said groove around said anvil block through the forward extremity of said element to keep the I mutually engageable surfaces of said anvil block and element free from dirt and other extraneous matter.

4. In a front end construction for rock drills, the combination of a casing having a drill steel slidable therein, an anvil block in abutment with said drill steel, an element Within which said anvil block is slidably guided, a groove within said element having pressure fluid supplied thereto, and an annular clearance between said element and anvil block leading from said groove to the forward extremity of said element through which the pressure fluid from said groove is free toflow for preventing the admission of dirt and other extraneous matter to the mutually engageable surfaces of said anvil block and element.

5. In a front end construction for rock drills, the combination of a casing having a drill steel slidable therein, an anvil block in abutment with said drill steel, an element within which said anvil block is slidably guided, a chamber within said casing within which said anvil block is free to slide, means for admitting pressure fluid through the forward extremity of said element around said anvil block into said chamber, an annular internal groove within said casing near the forward extremity thereof, and means for supplying pressure fluid from said chamber into said groove and therefrom around said drill steel through the forward extremity of said casing to prevent the admission of dirt and other extraneous matter to the mutually engageable surfaces of said drill steel and casing.

JOHN C. CURTIS. 

